The major industrial applications for hydrolases, e.g., lipases, saturases, palmitases and/or stearatases, include the food and beverage industry, as antistaling agents for bakery products, and in the production of margarine and other spreads with natural butter flavors; in waste systems; and in the pharmaceutical industry where they are used as digestive aids.
Processed oils and fats are a major component of foods, food additives and food processing aids, and are also important renewable raw materials for the chemical industry. They are available in large quantities from the processing of oilseeds from plants like rice bran, corn, rapeseed, canola, sunflower, olive, palm or soy. Other sources of valuable oils and fats include fish, restaurant waste, and rendered animal fats. These fats and oils are a mixture of triacylglycerides or lipids, i.e. fatty acids (FA) esterified on a glycerol scaffold. Each oil or fat contains a wide variety of different lipid structures, defined by the FA content and their regiochemical distribution on the glycerol backbone. These properties of the individual lipids determine the physical properties of the pure triacylglyceride. Hence, the triacylglyceride content of a fat or oil to a large extent determines the physical, chemical and biological properties of the oil. The value of lipids increases greatly as a function of their purity. High purity can be achieved by fractional chromatography or distillation, separating the desired triacylglyceride from the mixed background of the fat or oil source. However, this is costly and yields are often limited by the low levels at which the triacylglyceride occurs naturally. In addition, the ease of purifying the product is often compromised by the presence of many structurally and physically or chemically similar triacylglycerides in the oil.
An alternative to purifying triacylglycerides or other lipids from a natural source is to synthesize the lipids. The products of such processes are called structured lipids because they contain a defined set of fatty acids distributed in a defined manner on the glycerol backbone. The value of lipids also increases greatly by controlling the fatty acid content and distribution within the lipid. Elimination from triglycerides, fats or oils of undesirable FA, or replacement of FA with undesirable properties by fatty acids with better or more desirable chemical, physical or biological properties, increases the value of the lipids. In particular, a need exists for lipases that can hydrolyze, e.g. selectively hydrolyze, a saturated fatty acid (a “saturase”), or those that in particular, can hydrolyze, e.g. selectively hydrolyze, a palmitic acid (a “palmitase”) or a stearic acid (a “stearatase”) from a glycerol backbone. Lipases, such as saturases, e.g. palmitases and/or stearatases can be used to effect such control where the FA being removed, added or replaced are saturated fatty acids, e.g. palmitatic acid or stearic acid.